Racelog
This program is for motorcycle racers although much of could be use for other types of racing. It allows you to keep detailed records of each race to be used for decisions on what to do for setups on other races especially if you come back to a specific track. This one actually has a help file so I will not go into all the features here and how to use them. The current version is a .NET 2 and requires 2.x and above framework be installed to use. This application is for XP, Vista and Windows 7.
The Stop Watch tab is one of my favorites. I liked making this. I originally made it for a Tablet PC but will work fine with a normal laptop.
If you enter the length of the track it calculates the average speed for each lap.
Here is the link to the MSI installer. The program has many supporting DLLs, all .NET, so I am only providing it in and installer.
Click here to download.
The current version is 1.2.3.1